(1) Field of the Invention
The present invention relates to a display device for a vehicle, in which (a) a virtual image of an image projected on a projection area of a windshield of the vehicle, onto which area the image displayed on a display source is reflected by a reflecting member and (b) a front view of the vehicle to be seen from an eye point of the vehicle through the windshield are seen in a superimposed manner, and to a supporting method for adjusting a display position thereof.
(2) Description of the Related Art
Recently, accompanied with increment and diversification of information required by a driver during a drive of a vehicle, in order to improve visibility, a projection type display device for a vehicle being called a head up display device (HUD device) has been adopted, in which an image is displayed as a virtual image thereof on a windshield of the vehicle and subjected to be seen by the driver in a superimposed manner together with a front view of the vehicle through the windshield. So far, the HUD device has been provided with a mechanism for adjusting a position of a display image in order to assure that the driver can see the display image even when an eye point of the driver shifts within an eye range.
The following examples are known as a HUD device including such a mechanism for adjusting a position of a display image. A HUD device described in Japanese Patent Application Laid-Open No. H7-266925 includes: a reflecting member for reflecting light from a light source passing through a display indicator on a reflecting surface by a predetermined angle; and a motor for adjusting an angle in an up-and-down direction of the reflecting surface of the reflecting member, thereby enabling the adjustment of the angle.
A HUD device described in Japanese Patent Application Laid-Open No. 2002-307977 includes a control switch for carrying out a positional adjustment of a display image, so that a mark by which a display range of a display image can be seen is displayed when the switch is operated, thereby supporting the positional adjustment.
However, when a driver, whose display position setting is different from that of a former different driver, uses the HUD device, there is a possibility that the display image is partly missing or that nothing can be seen by the driver. In order to solve this problem, according to a HUD device described in Japanese Patent Application Laid-Open No. 2006-15941, a reflection angle of the reflecting member is detected, a reflection point corresponding to the reflection angle is specified, and a positional relation between the reflection point and an eye range is displayed, so that a driver can easily judge a method of adjusting the reflecting member even when a situation, in which nothing can be seen by the driver, takes place.
However, the HUD device described in Japanese Patent Application Laid-Open No. 2006-15941 needs to include a positional relation display means, by which a positional relation between the reflection point and an eye range is displayed. The solution by using such a HUD device having the positional relation display means only for the adjustment of the reflecting member is not realistic taking a necessary cost thereof into consideration. Accordingly, when trying to solve the problem that it is difficult to adjust a display position satisfying the driver's desire, there is still a problem of cost-up and again, when a driver, whose display position setting is different from that of a former different driver, uses the HUD device, there is a possibility that the display image is partly missing or that nothing can be seen by the driver.